Building A Vacuum Table

I've been working on a setup for making my own prints, and I recently finished building a vacuum table.

My main model for this project was the vacuum table built by Pelican Print Shop. Their process post detailing the construction of their own table was a key guide in not only selecting materials and components, but in figuring out the assembly steps for the hardware as well. I'd seen/read about vac tables with top surfaces made of recycled desk wood, linoleum, countertop, plexiglass, whiteboard, etc., but I followed Pelican's example and committed the biggest chunk of my project budget to a quarter inch sheet of aluminum for my top. I knew a slab of Al like that would be sturdy as anything, would be easy to clean in case of ink spills, and would look great too. I sized the slab based on the size of the 25" x 36" screens I have and how thick I wanted the frame of the table's hollow to be, arriving at a final measurement of 30 by 41 inches for the tabletop area.

Once I had my aluminum, the first physical step was marking out where the underside of the slab would connect to the frame of the air chamber and the frame of the screen. I sharpied in an inch-by-inch grid for the main spread of holes and marks for the pilot holes for bolting the top to the frame.

(An area of 21 by 31 inches is... )

Next on the shopping list was the wood for the bottom and sides of the air chamber: a sheet of 3/4-inch-thick plywood and some 2-inch-thick square beams made of who knows what (I was not exactly picky at this step). The base of the table was set to be the same size as the top, but I made sure the frame of the hollow actually ended up an inch shorter than that 30" by 41" size top surface size (you'll see why in about 20 images or so).

After everything was sanded appropriately (I left the lowermost edge of the side beams rough to give the wood glue more to grip), I began building the perimeter of the air chamber. Each beam + base contact got a line of "wood filler" close to the outer edge and a line of Gorilla Glue hugging the inside of that. The wood filler I used was a little too thick when I first started to apply it, but customer support at Famowood helpfully let me know that I could thin out the solvent mix with nail polish remover (which seemed to work).
For a more even pressure (and more weight) on the beams while the glue was drying, I laid in some of my extra 2-by-2 beams for support, set the aluminum on top of all that...

And finally clamped the slab near the working edge with pony clamps.

I did this for each side beam, giving each about twenty-four hours of glue + clamp pressure, scraping away the squeezed out excess wood filler every next morning. To save time, I even started drilling the grid of holes while the aluminum was clamped in place.

Ultimately, the drilling took about two weeks. (I think I could have managed it in ten days if I hadn't needed to catch up on Elementary.) I have no idea how Pelican managed to get their grid done in "two days". They are wizards, probably. My only guess is that maybe my aluminum sheet was a harder grade of metal? I did all the drilling outside, so I scheduled my hours for the factors of:

Only making noise during the day

The need to eat/sleep

Taking care to give the drill motor a chance to cool down

And my hands' tendency to feel like tuning forks after several hours of power drilling.

The holes typically took between one to three minutes each. Sometimes holes would take something like fifty seconds, shimmering ribbons of metal twirling away like the skirts of flamenco dancers. Sometimes holes would just become inert sockets, clogging the bit with chops of aluminum right from the start. That Nikx Stikx stuff was crucial, and saved me from having to spatter WD-40 everywhere.

After all the sides were glued in place, I put two nails into the "front" edge, flipped the wood base over and bored out a hole for the vacuum connection with a misused wood-boring bit and a chunk of spinning stone polisher. Once I had a hole in the plywood, I twisted in a short length of threaded pvc...

And sealed up the edges on the inside with a mixture of sawdust and Gorilla Glue.

I returned to the hardware store and got some of my spare 2-by-2 lengths sliced to half-inch wide beams, and put a few air-circulation holes in those.

This was completely unnecessary with the spacing I was using, but I made sure that the holes in these inner beams lined up (for airflow).

The most important part of this step was ensuring that these beams were placed so that they'd fit between the rows of holes in the surface slab and not block any of the grid once the aluminum was laid in place. After careful measuring, I affixed them to the base board with the now familiar process of gluing them down and clamping the aluminum on top of them for a day. I knew the outer frame was solid, and that there was almost no chance of the aluminum slab warping, but that if I was going to be putting pressure on the table during printing, it could only be a good idea to have some inner support beams:

The structure of the air chamber was almost done, but before I finished the final step, I used that same wood-boring bit to make a hole in that "extra" inch of base board on the front end.

Because the wood I used for the side beams was only cut to lengths (and not custom-cut to be even on all angles) my corners were far from exactly fitting. In order to make sure the air chamber was fully sealed and only pulling air from the top grid, I applied a few globs of that sawdust-and-Gorilla-Glue mix to the inner corners and gave it a few hours to expand/dry.

Then I flipped the table base again and installed the threaded pipe bases (and threaded pipes) for the table legs (again, copying Pelican's setup to the letter).

I loved this idea for the legs. The pipes are super solid, I can unscrew them in case I ever want to transport the table anywhere, and best of all: having custom pipe lengths means that I can save my spine and set the height of the table to "unnaturally tall".

While the base was still upside-down, the next step was installing the vacuum motor:

Once again, I have Pelican to thank for pointing me towards the Eureka Yellowjacket. It's a great size, comes with a mounting brace, and turns on with a simple circuit connection. I wedged the other end of the vinyl tubing into the yellowjacket's intake valve and used some brackets left over from a framing project to gather up the slack of the twin circuit wires.

With that wiring in mind, I used a much larger drill bit to bore a hole near the "front" end of the aluminum...

And twisted in a little toggle switch:

It's right up near the edge, but I had to be sure the switch mechanism could fully spin and unscrew from its hole in that inch gap in front of the air chamber frame (in case I ever want to store or transport the table without worrying about the switch bending or snapping off).

I'd read good things about floor pedal switches for vacuum tables (like the way they can keep your hands free while you're printing), but I think setup for turning the vacuum on and off should work fine.

I removed the switch, finished drilling the last eighty or so holes in the grid, and flipped the slab right-side-up to sand/smooth it. Drilling from the underside would often push up these little bump chads of loose aluminum around the surface holes, so I went over the top with some fine sand paper and steel wool until it was Ms-Frizzle-friction-field-trip smooth. Then I set the sheet of aluminum over a perimeter line of silicone sealant on the wooden frame. I didn't put any sealant on the inner support beams, because I didn't want it to squeeze out and block up any holes. With those pony clamps holding everything in place (with magazines between them and the tabletop so as not to press circle marks into the aluminum), I used those pilot holes I'd drilled...

to drill in two bolts on each of the longer sides:

(Part of the reason I put those nails in the front end of the base-to-side-beam connection only was because having anything like a bolt on the front edge of the table would kill any chance of printing on paper longer than the screen.)

I then threaded the vacuum's circuit wires through that hole in the wood and connected them to the re-installed switch:

On the advice of this post I went with a pair of Jiffy screen clamps bolted right to the the back edge:

I'd considered mounting the clamps to a separate piece of wood so that I could raise or lower them in tandem depending on the thickness of what I was printing on (this is usually the best idea), but I feel righteous about dedicating the setup to just printing on paper.

Here are the clamps holding a screen in place:

And a screen propped up by a jar of ink:

And a shot of the spread of holes:

And that's it!

I put down piece of paper and flipped the switch and the table pulled the sheet flat like a spell. I still need to rig up a "kickstand" for the screens and figure out how I'm going to build a drying rack, but I'm a lot closer to being able to create prints whenever I want.